From the archives of the AFIP: Pediatric liver masses: radiologic-pathologic correlation. Part 2. Malignant tumors.

Malignant primary hepatic tumors in children include lesions unique to the pediatric age group and others that are more common in adults. Important considerations when evaluating a child with a liver tumor are the age of the patient, laboratory findings, and specific imaging features. The most common primary malignant hepatic tumor in the pediatric population, hepatoblastoma occurs almost exclusively in patients younger than 5 years with no history of liver disease. Hepatoblastoma is associated with elevated serum α-fetoprotein (AFP) level and appears predominantly solid. Hepatocellular carcinoma (HCC) is the most common malignant liver tumor in older children, often with a history of liver disease. HCC is associated with elevated serum AFP level and also appears as a solid mass. Fibrolamellar carcinoma occurs in adolescents without elevated AFP level and contains a T2-hypointense fibrous scar that usually does not enhance. Undifferentiated (embryonal) sarcoma occurs in young children, contains cystic and mucoid components, and mimics a cyst at magnetic resonance imaging and computed tomography but appears solid at ultrasonography. Epithelioid hemangioendothelioma is a multifocal vascular tumor in older children with a distinctive imaging appearance of confluent peripheral nodules with adjacent capsular retraction. Angiosarcoma rarely occurs in young children and frequently shows evidence of hemorrhage. Embryonal rhabdomyosarcoma of the biliary tree is unique to children, usually under 5 years of age, and frequently demonstrates an intraductal growth pattern. Knowledge of the pathologic features of these tumors and their imaging appearances can help radiologists offer an appropriate differential diagnosis and management plan.